Key Takeaways

  • Interim 6-month data from the LIGHTHOUSE trial show favorable safety and meaningful structural and functional improvements with ATSN-201 in XLRS patients
  • Foveal schisis closure was achieved in 67% of treated adults, with no comparable changes in untreated eyes and no serious adverse events reported
  • Enrollment is underway for the phase 3 pivotal cohort

Atsena Therapeutics announced interim 6-month results from Part B of its ongoing phase 1/2/3 LIGHTHOUSE trial evaluating ATSN-201, an investigational gene therapy for X-linked retinoschisis (XLRS). The data were presented May 1 at the Foundation Fighting Blindness Retinal Therapeutics Innovation Summit in Denver.

Atsena reported that findings from Part B closely replicate outcomes seen in Part A, including a favorable safety profile and meaningful structural and functional improvements.

“Part B of our LIGHTHOUSE study is delivering exactly as we expected—a favorable safety profile, schisis resolution, and functional improvements at 6 months that closely replicate what we observed at the same time point in Part A,” said Shannon Boye, PhD, co-founder and chief scientific officer of Atsena. “Foveal schisis closure was observed in four of six treated adults, and there was no structural change observed in untreated control subjects or untreated contralateral eyes.”

The study’s adult cohort includes nine participants, alongside three pediatric patients. Adults are divided into two treatment arms evaluating different injection volumes and a control arm, with control participants eligible for treatment after 1 year. The trial continues to assess safety and efficacy through measures such as microperimetry, visual acuity, and retinal structure.

Among the key findings, 67% of treated adults in Cohort 4 achieved foveal schisis closure at 6 months, while no such improvements were observed in untreated eyes. Functional outcomes, including microperimetry responses, mirrored those seen in earlier cohorts. Importantly, no serious adverse events, retinal detachments, or study discontinuations were reported. Any subretinal deposits observed in a subset of patients resolved with temporary steroid treatment.

Pediatric patients, ages 8 to 12, also demonstrated a clean safety profile, with no serious adverse events or treatment-related complications reported.

Atsena has now initiated Part C, the pivotal phase 3 portion of the LIGHTHOUSE trial, marking a significant step toward potential regulatory approval. The registrational study will enroll 76 patients across North America and Europe, comparing ATSN-201 treatment with a control group observed for 12 months before having the option to receive therapy.

“Enrollment in the pivotal Part C cohort is now underway, and this marks a significant milestone for patients with XLRS and for Atsena,” said Kenji Fujita, MD, chief medical officer. “ATSN-201 is the first gene therapy to advance to a registrational trial for XLRS, a disease with no approved treatments. We remain on track for a BLA filing in 2028.”

The primary endpoint for Part C is microperimetry at 52 weeks, aligned with regulatory guidance from the FDA and the European Medicines Agency. Secondary endpoints include visual acuity and optical coherence tomography outcomes. Enrollment is expected to conclude in the first quarter of 2027.